CHICAGO – Lt. Gov. Sheila Simon said she is in favor of a bill allowing the medical use of marijuana, explaining Sunday that testimony from seriously ill veterans and other patients helped change her mind.

"As a former prosecutor my first reaction was, 'I'm not interested in changing our laws on medical marijuana,'" she told The Associated Press in an interview Sunday. But she said that after hearing from patients and reading up on the bill, she's convinced the regulations are strict enough.

Backers of the measure, which has cleared the Illinois House and awaits a Senate vote, have said the same thing.

The plan, touted as the strictest in the nation among states that have legalized medical marijuana, would authorize physicians to prescribe marijuana to patients with whom they have an existing relationship and who are living with at least one of more than 30 medical conditions, including cancer.

The proposal creates a framework for a pilot program that includes requiring patients and caregivers to undergo background checks. It also sets a 2.5-ounce limit per patient per purchase and sets out state-regulated dispensaries.

Supporters say marijuana can relieve continual pain without the detrimental side effects of prescription drugs. But opponents say the program could encourage recreational use, especially among teenagers.

The Illinois Association of Chiefs of Police and the Illinois Sheriffs' Association are opposed to the measure, saying there's no sure way to figure out whether a motorist is driving under the influence of marijuana.

But Simon told the AP the bill is strict enough to prevent misuse.

"It does a good job of both getting medical marijuana to people who need and keeping it away from those who don't," she said.

Gov. Pat Quinn, a Chicago Democrat, has been noncommittal whether he would sign the bill, saying instead that he is open-minded to the idea.

Simon is weighing a run for another statewide office instead of seeking another term as lieutenant governor. The Carbondale Democrat declined Sunday to say which office she will run for, saying she will wait to see how other shape up.

Simon is likely choosing between Illinois' attorney general, comptroller or treasurer. In recent months, Simon has played up her law-related background and accomplishments including as a pro bono lawyer and prosecutor.

Her decision comes as the 2014 governor's race is heating up and Illinois Attorney General Lisa Madigan is weighing a possible challenge to Quinn.